Question

In Young’s experiment the interval between the slits is 0.200 mm. For the light of wavelength 600 mμ, interference fringes are formed on a screen at a distance of 80.0 cm. (i) What is the distance of the second dark fringe from the central fringe? (ii) What is the distance of the second bright fringe from the central fringe?   

Solution

Correct option is

0.360 cm, 0.480 cm

 

(i) In Young’s double-slit experiment, the distance of the m th dark fringe from the central (bright) fringe is given by

                      

Here d = 0.200 mm = 0.2000 cm, D = 80.0 cm, λ = 600 milimicron* = 600 × 10–7cm. For the second dark fringe m = 2. Hence the distance of the second dark fringe from the central fringe is

                       

(ii) The distance of the m th bright fringe from the central fringe is given by  

                     

For the second-order bright fringe, m = 2. Hence the distance of the second bright fringe from the central fringe is  

                     

SIMILAR QUESTIONS

Q1

The number of waves in a 4-cm thick strip of glass is the same as in 5-cm water, when the same monochromatic light travels in them. If the refractive index of water be 4/3, what will be of glass?

Q2

What is the content of energy in X-ray photon of wavelength 10 Ã…? Given J-s,  

Q3

Calculate de-Broglie wavelength for an electron and a proton moving with the same speed of 105 m/s. (me = 9.1×10 –31 kg, mp = 1.67 × 10 –27 kg and h = 6.63 × 10 –34 Js).

Q4

The ratio of intensities of two waves is 25:16. What is the ratio of amplitudes? If these two waves produce interference, then find the ratio of maximum and minimum intensities.

Q5

Two waves of same frequency have amplitude in the ratio 2:1. Find the ratio of the maximum and the minimum amplitudes and intensities in the region of interference. 

Q6

 

Two coherent sources X and Y of light of wavelength

λ = 6.2 × 10 –5 cm, produce interference. If both the sources are in the same phase and P is an arbitrary observation point, then calculate XP – YPwhen the point P is (i) At the bright band of 10th order, (ii) At the dark band between third and fourth order maxima.

Q7

In Young’s experiment on interference of light a fringe of width 0.04 cm is obtained on a screen placed at a distance of 50 cm from the slits when the wavelength of the light used is 5000 Ã…. If the distance of the screen from the slits remains unchanged, what will be the width of the fringe if light of wavelength 4000 Ã… is used? 

Q8

The fringe-width is obtained as 0.060 cm on using light of wavelength 5000Ã… in Young’s experiment. What value of wavelength of light should be taken so that the width of the fringe on the screen could be obtained as 0.040 m, if the distance of screen from the slit is halved?

Q9

 

In a two-slit experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the slits. If the screen is moved by  towards the slits, the change in fringe-width is . If the distance between the slits is 10–3 

M, calculate the wavelength of the light used. 

Q10

Microwave from a transmitter are directed normally towards a plane reflector. A detector. A detector moves along the normal to the reflector. Between positions of 14 successive maxima the detector travels a distance 0.14 m. The frequency of the transmitter is (c = 3 × 108 m/s)